package com.interview.write;

public class DemoEight {
        /**
         * 快速排序算法
         */

        public static void quickSort(int[] arr,int low,int high){
            int i,j,temp,t;
            if(low>high){
                return;
            }
            i=low;
            j=high;
            //temp就是基准位
            temp = arr[low];

            while (i<j) {
                //先看右边，依次往左递减
                while (temp<=arr[j]&&i<j) {
                    j--;
                }
                //再看左边，依次往右递增
                while (temp>=arr[i]&&i<j) {
                    i++;
                }
                //如果满足条件则交换
                if (i<j) {
                    t = arr[j];
                    arr[j] = arr[i];
                    arr[i] = t;
                }

            }
            //最后将基准为与i和j相等位置的数字交换
            arr[low] = arr[i];
            arr[i] = temp;
            //递归调用左半数组
            quickSort(arr, low, j-1);
            //递归调用右半数组
            quickSort(arr, j+1, high);
        }


    public static void main(String[] args){
        int[] arr = {7,10,2,4,7,1,8,5,19};
        quickSort(arr, 0, arr.length-1);
        for (int i = 0; i < arr.length; i++) {
            System.out.print(arr[i]+" ");
        }
        System.out.println();
    }
}
